Mike told his son Jeff to choose what pet Mike would be during his vacation. Jeff thought about it. There was a reason he hadn't had a pet before. The neighbors, the Willises hated dogs. Jeff wanted a pet that he could play with outside but the Willises already had a reputation for harassing everyone about leash laws and other restrictions. The Willises had even succeeded in getting five dog owning families to either move away or get rid of their dogs and the Willises were proud of their success.
Jeff thought about how to have a pet without harassment from the Willises. "Maybe if he was still human enough to understand things like property lines or car safety. Then again, he wants to take a break from thoughts of responsibilities. Can I control specific settings to make him dog-like in certain ways but human in others?"
Jeff studied and yes there were some specific changes he could make. He set his dad's sense of territoriality to be human-like, to understand that boundaries are marked by lines, not scents. He also kept his dad's sense of cars as vehicles, not threatening beasts. He also kept his dad's ability to speak English although his dad's mind would mostly be dog thoughts. Dad would also still use a toilet and not poop outside. Other than a few minor human-like traits to help him behave, Dad would otherwise think completely like a dog.
Then it was time to decide physical changes. If dad was going to have to use a toilet, he would need to retain his human hands. Running on all fours would be out. Jeff also didn't want to risk puppies so Dad would keep his human genitals. Jeff also set his dad's orientation to exclusively gay, having zero interest in females. What he wound up doing was turning his dad into an anthro-dog.